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CLINICAL 

THERMOMETERS AND THERMOGRAPHY. 



Considering that clinical thermometry was hardly spoken of 
in this country before 1867, and that it was first introduced in 
a half dozen of our hospitals during that year, it speaks well 
for the quickness of mind of the American practitioners, and 
for the energy of the American manufacturers of philosophical 
instruments, to see clinical thermometers wherever physic is 
practised, and to read about thermometry and thermography 
in all the medical publications. Indeed, in the past eight years, 
it has become more impossible to practise physic without a ther- 
mometer than it was before without a lancet. 

Carried by the same movement, American women— who 
always want, to learn what is good for them to know — seeing 
the diagnostic power physicians derive from thermometric in- 
dications, have begun to learn the simple rules by which the 
thermometer indicates the differences between fatigue and 
fever, uneasiness and prodromic temperatures, the cases man- 
ageable by simple nursing from those which require a prompt 
medical intervention (in Manual of Thermometry for Mothers, 
etc., by Edward Seguin, M.D., at G-. P. Putnam's Sons) ; and 
now, in well posted circles, the mother takes the temperature 
of her sii-k before calling the physician, and later, between his 
visits ; so that he can by her know even what he has not seen. 

Other classes are equally interested in the findings of human 
thermometry : the managers of schools, of asylums, of insurance 
companies ; the chiefs of large industrial, military, and naval 
establishments, etc. But, to restrict our remarks to the two 
classes first named, the physicians and the mothers, we must 
say that their patronage alone creates an immense demand, 
which must be met by the largest production of the best instru- 
ments. Unlike most of the European countries, where the 
people at large are poor and unalphabetic, the American peo- 
ple breeds no inferior classes and receives an unequalled 
average education, which enables all not only to read the 
weather-thermometer, but to comprehend human thermometry. 

7i . t/ 



2 



HOW TO MAKE CORRECT THERMOMETERS. 



But, to become the compass of physicians and the gnide of 
mothers, thermometry requires accurate instruments. Other- 
wise a single error of a half degree may endanger life, a series 
of errors of a tenth of a degree may falsify a diagnosis, the 
miss of a rise or fall consequent to a dose may cause its fatal 
repetition, etc. Indeed, every siqjkly temperature having a 
meaning, every thermometric operation having its importance, 
every instrument must be trustworthy ; every good thermome- 
ter increases the usefulness of thermometry, and every bad one 
imperils — with the lives of patients — the very art it pretends to 
serve. | 

The manufacture of thousands of equally accurate, therefore 
concordant, thermometers is an actual problem, but one not so 
easily solved as it may seem to an outsider, because skill alone 
does not suffice to make them perfect ; another element — time 
— enters into their composition. When skilfully made, time 
must be allowed to their materials to harmonize. The glass 
tube shrinks, the mercury moves, causing relative displacements 
of several degrees during the six first months, of several tenths 
of a degree during eighteen or twenty months more. There- 
fore, the best makers cannot make good thermometers unless 
they put off their graduation at least two years. After this 
lapse of time between the making of the instruments and the 
marking of their scale, it is to be expected that, from the cen- 
tral point of health, 98.6° Fahrenheit, equal to 37° Centigrade, 
equal to of the physiological scale, up to 45° C, and below 
to 33° C, there will be no deviation larger than the twentieth 
of a degree from the metrical etalon (standard measure) depos- 
ited at the Smithsonian Institute. Such deviations are met 
with in the very best instruments, whose makers take pride in 
having these infinitesimal errors consigned in a certificate from 
the Kew Observatory, where their instruments are tested on the 
etalon. 

Till a similar measure of verification be adopted in this 
country, it becomes not only a question of good workmanship, 
but of good faith, to produce thermometers equal to those of 
England. If we do, an official control is unnecessary, an im- 
mense patronage will be our reward, and a large share in the 
next progress of physic will be our honor. 

On the perfection of the instruments the manufacturer has 
much influence ; on the choice of a thermometric scale hardly 
any. This choice is generally determined by tradition, exam- 
ple, habit, sooner than by a sound criticism. What the manu- 
facturer can do is to produce them all, and to throw them all 
in the market, with hardly an intimation as to their defects, or 
adaptability to the wants of the clinic, and of the divers sys- 
tems of thermography. 



THE PHYSIOLOGICAL THERMOMETER. 



3 



1st. The scale of Keaumur, though yet of great authority in 
physics, and employed in medicine by some distinguished men, 
can be here but a cause of trouble and of obscuration of the 
problems of clinical thermometry. 

2d. The Fahrenheit scale is generally used in this country 
as in England, though many physicians of good standing object 
to it, because : a. Its figures have no common divisor with the 
other measures of the body and its symptoms, b. Its central 
figure, O, is 98.6° distant from the central point of the drama 
of life and death, a distance which precludes any mathematical 
reckoning thereof, c. It requires the constant reference to 
tables of equivalents when its findings have to be compared 
with those of other scales. 

3d. The Centigrade scale is used by many nations as part of 
a uniform reckoning (the metric system) which offers a common 
divisor for all the pathological quantities mathematically appre- 
ciable. The only objection to its use in medical records is that 
its central figure, O, is 37° distant from the health point, where- 
f rom must start all the calculations upon the course of diseases, 
the effects of medication, food, etc. However, this difficulty is 
avoided by displacing the O of the Centigrade scale from the 
point of melting snow to that of human health, without alter- 
ing its Centigrade divisions in degrees. 



Physiological Thermometer. 




4th. This modification constitutes the Physiological Scale, 
whose figures are calculable in all proportions with those of any 
other pathological quantities worth recording, and by mentally 
adding thirty-seven to the findings. The physiological scale 
may be, like the others, reproduced by curves {see graphic 
tables, p. 5), and is the only one whose figures can be mathemat- 
ically treated {see mathematic tables of vital signs, p. 4). 

The self-registering thermometer is the only one which needs 
to be prepared for insertion by gentle swings of the arm or 
shakes of the hand, to put the index down below the point at 
which the body-temperature is expected to raise it again. Other- 
wise the less movement the best ; some persons have to break 
or spoil a few thermometers to understand this. 

Before applying the fever-thermometer, it saves time to warm 
it to about ten degrees less than the nor me, and to dry the axilla 
if moist. The insertion takes place by putting the instrument 
half-way under the fold which marks the junction of the chest 
and arm, and crossing the former on the latter for about seven 
minutes, or till the mercury is seen to rise no more. 



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GRAPHIC RECORD OF VITAL 

DATE, NAME, DISEASE 



SIGNS. 



DATS OF 
DISEASE. 



110° 
109° 
108° 
107° 
106° 
105° 
104° 
103° 
102° 
101° 



98° 

96° 

95° 
T50~ 
140 
~130~ 
120 
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100 
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70 

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40 

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ME M E I M B I M E | H E | MB I III 



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6 



THE SURFACE THERMOMETER. 



The other kinds of thermometers demand the same care. 
They are included in two classes : one whose varied forms are de- 
vised to satisfy artistic tastes, or calculated to diminish the chances 
of breakage ; the other, whose forms or different philosophical 
principle are intended to fulfil special thermic indications. 

The first category needs no illustration, bearing names gene- 
rally sufficiently descriptive : the curved, the pencil case, the 
screw case, etc., or the name of their inventor. 

The second category contains the instruments whose form or 
philosophical principle permit to measure body-temperatures 
which the fever-thermometer cannot well reach, nor correctly 
express; the principal ones are the surface-thermometer of 
Winternitz of Vienna, which has not been yet executed in this 
country. 



The Surface Thermometer. 




In the surface thermometer the form alone is interesting, as 
calculated to meet (by light adaptation) almost any part of the 
periphery whose combustion and f rigeration have to be observed. 
This is done simultaneously with two surface thermometers, or 
with one successively applied on a sick and on a healthy corre- 
sponding point, and the results are recorded as seen on the 
mathematical chart, page 4. 



The Thermoscope. 



It is its principle which — old in physics — has but recently 
been applied to medical observation. Taking advantage of the 
sensitiveness of air to heat and cold, the air contained in the 
reservoir B is corked up by a drop of water I, which, moving, 
in the tube T as the air in the bulb is dilated or contracted, pro- 
gresses along the scale S placed outside. 

To make the thermoscope ready for clinical or maternal use,' 
its bulb is heated over a lamp or fire, sooner in a bowl of hot 
water, and when the air contained in the bulb is dilated a few 
degrees above the ambient temperature, the open end is quickly 
plunged in — an inch deep — and quickly withdrawn from 



THE THERMOSCOPE. 



7 



another bowl of cold water. The drop or two which will have 
then entered the mouth, is seen to run up the tube. If it stops 
near the bulb, it will be the index of the thermoscope ; if it 
stops sooner, say two or three inches from the mouth, or if it 
runs into the bulb, the latter was too cold or too hot ; we have 
to jerk away that drop of water and recommence ; three or four 
trials to obtain a good water-index take hardly a minute. 

In this condition, the air contained behind the water-index 
makes itself isothermal to the ambient temperature, and the 
thermoscope is ready. 

Simpler yet : Overheat the bulb, let the water run in it. When 
you want an index, invert the instrument, apply your hand on 
top ; some water will descend in the tube and form an index ; 
then quick, fit your scale to it, look at your watch, all is ready. 

When the external heat is near blood-heat, the air in the 
bulb having become isothermal to the former cannot be much 
dilated by the contact of fever-heat ; therefore the index will 
indicate nothing. But in this circumstance, the bulb being 
previously plunged in cold water, the index will soon be im- 
pressible again. For mathematical observations the tempera- 
ture of the cold water so used is taken, and serves as starting 
point of the excursus, just as that of the ambient air serves in 
ordinary conditions when exactitude is desirable ; any weather- 
thermometer is good to establish this comparison. 

The thermoscope is applied anywhere an anomaly of calor- 
icity is known or suspected. Its habitual place {lieu election) 
is not, however, the axilla ; it is the shut-hand. In ten to fif- 
teen seconds the index has attained the maximum height or 
fall of any significance. To read it, we mark the starting-point 
of the index, the terminus of its course, and the time (in 
seconds) to reach it. To take more mathematical observations, 
a mobile scale is attached to the stem, and made to slide, in 
order to put its lowest figure on a level with the head of the 
water-index, or the converse to take frigid temperatures ; so 
that a thermoscope is always correct — that is more than can be 
said of most of our clinical thermometers. 

But with or without a scale, it gives, by contact, indications, 
(a) at the start of the volume of heat escaping by radiation, (b) 
at the end of its course, of the jportee or reach of its velocity ; 
whilst, without contact, by gently blowing on the bulb, it shows 
the degree of combustion which takes place in the lungs, and 
other phenomena of ustion too long to explain here. 

Without a scale a mother can tell at what hour the index 
rose quicker and higher, or quicker only, and not so high, etc. 
Without a scale, too, a physician who well knows his case, and 
is short of time, can, in less than ten seconds, decide upon the 
dynamic conditions of the next twelve or twenty-four hours 



021 623 838 2 

8 THE NECROMETER OF EVERY FAMILY. 

dependent on the waste of caloricity by radiation — that is to 
say of life itself in many eases — and prescribe accordingly. 

The thoracoscope may often be called to decide about the 
precise seat of an affection indicated only by general, reflex 
and regional symptoms. Prof. Sayre informs me that in a case 
of sacro-iliac disease, so obscure that all other means of diag- 
nosis had failed, the thermoscope indicated the place of lesion. 
(J. S. Green, in New York Medical Journal, Dec, 1875, p. 
til 5.) It criticises and explains these enigmatic temperatures 
which ostensibly remain near the norme after a deadly acci- 
dent, or otherwise appear before death ; and which, made up 
of a high fever and shock or hemorrhage, are compound tem- 
peratures whose composition cannot be analyzed by the ordi- 
nary thermometer, but is found out by the more sensitive 
thermoscope. ( , 

Passing from the sick-chamber to the dead-house, the ther- 
moscope proves to be the only necrometer founded upon the 
law of radiation, as per example : — Being applied below the 
sternum of a body brought three hours previously to the dead- 
house of the Bellevue Hospital, the index did not move from 
the position it had taken in the ambient temperature of a very 
cold January day, but put in the axilla it slowly and steadily 
rose 6 centimetres = 2 inches ; there was yet vital heat, though 
a thermometer inserted instead of the thermoscope failed to 
demonstrate any. 

So the thermoscope, in contact with the living, shows the 
activity of their caloricity ; and, in contact with the dead, ceases 
to indicate heat only when and where organic combustion 
becomes progressively extinct. As thousands are and have been 
buried alive, the invention of a true necrometer excites a deep 
interest, intensified, if possible, since cremation is mooted. For 
some have knocked at their coffins and re-entered the world ; 
but of what use would it be to knock for help inside of the fur- 
nace ? The proof of death is wanted now more than ever ; the 
thermoscope gives this proof alike to the savant and to the 
ignorant. 

~No family, and certainly no physician, must be without it. 
Few persons are without a weather-thermometer, but how many 
possess the instruments which bring home the knowledge of 
these internal temperatures which are warnings of imperilled 
life '? So, let the gardener watch the zero of external tempera- 
ture which will kill his cucumbers, but let the physician warn 
the mother of the significance of the zero of the physiological 
thermometer for the security of her children. 

(See Medical Thermometry and Human Temperature, by 
E. Seguin, 2d ed., pp. 430, W. Wood & Co., publishers, 27 
Great Jones Street, New York.) 



